<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>测试定时任务</title>
</head>
<body>
<script>
    // setTimeout(function (){alert("哈哈")},3000);
    function test(){
        alert("haha")
    }
    setInterval(test,3000);
</script>
</body>
</html>